gis: gdal: The OGRGeometry `srs` property is now mutable, and added the `srid` property.

git-svn-id: http://code.djangoproject.com/svn/django/branches/gis@6460 bcc190cf-cafb-0310-a4f2-bffc1f526a37

3 files changed, 69 insertions, 19 deletions

diff --git a/django/contrib/gis/gdal/geometries.py b/django/contrib/gis/gdal/geometries.py
index 4818a8fa1f..c997718b8c 100644
--- a/django/contrib/gis/gdal/geometries.py
+++ b/django/contrib/gis/gdal/geometries.py
@@ -39,7 +39,7 @@
     True
 """
 # types & ctypes
-from types import IntType, StringType
+from types import IntType, StringType, UnicodeType
 from ctypes import byref, string_at, c_char_p, c_double, c_int, c_void_p
 
 # Getting GDAL prerequisites
@@ -181,8 +181,8 @@ class OGRGeometry(object):
         "Returns the number of Points in this Geometry."
         return self.point_count
 
-    @property
-    def srs(self):
+    # The SRS property
+    def get_srs(self):
         "Returns the Spatial Reference for this Geometry."
         srs_ptr = lgdal.OGR_G_GetSpatialReference(self._g)
         if srs_ptr:
@@ -190,6 +190,32 @@ class OGRGeometry(object):
         else:
             return None
 
+    def set_srs(self, srs):
+        "Sets the SpatialReference for this geometry."
+        if isinstance(srs, SpatialReference):
+            srs_ptr = lgdal.OSRClone(srs._srs)
+        elif isinstance(srs, (StringType, UnicodeType, IntType)):
+            sr = SpatialReference(srs)
+            srs_ptr = lgdal.OSRClone(sr._srs)
+        else:
+            raise TypeError('Cannot assign spatial reference with object of type: %s' % type(srs))
+        lgdal.OGR_G_AssignSpatialReference(self._g, srs_ptr)
+
+    srs = property(get_srs, set_srs)
+
+    # The SRID property
+    def get_srid(self):
+        if self.srs: return self.srs.srid
+        else: return None
+
+    def set_srid(self, srid):
+        if isinstance(srid, IntType):
+            self.srs = srid
+        else:
+            raise TypeError('SRID must be set with an integer.')
+
+    srid = property(get_srid, set_srid)
+
     @property
     def geom_type(self):
         "Returns the Type for this Geometry."
diff --git a/django/contrib/gis/gdal/srs.py b/django/contrib/gis/gdal/srs.py
index fea050afba..243df6e4bb 100644
--- a/django/contrib/gis/gdal/srs.py
+++ b/django/contrib/gis/gdal/srs.py
@@ -1,15 +1,3 @@
-import re
-from types import StringType, UnicodeType, TupleType
-from ctypes import \
-     c_char_p, c_int, c_double, c_void_p, POINTER, \
-     byref, string_at, create_string_buffer
-
-# Getting the GDAL C Library
-from django.contrib.gis.gdal.libgdal import lgdal
-
-# Getting the error checking routine and exceptions
-from django.contrib.gis.gdal.error import check_err, OGRException, SRSException
-
 """
   The Spatial Reference class, represensents OGR Spatial Reference objects.
 
@@ -38,6 +26,18 @@ from django.contrib.gis.gdal.error import check_err, OGRException, SRSException
   >>> print srs.name
   NAD83 / Texas South Central
 """
+import re
+from types import StringType, UnicodeType, TupleType
+from ctypes import \
+     c_char_p, c_int, c_double, c_void_p, POINTER, \
+     byref, string_at, create_string_buffer
+
+# Getting the GDAL C Library
+from django.contrib.gis.gdal.libgdal import lgdal
+
+# Getting the error checking routine and exceptions
+from django.contrib.gis.gdal.error import check_err, OGRException, SRSException
+
 #### ctypes function prototypes ####
 def ellipsis_func(f):
     """
@@ -204,7 +204,10 @@ class SpatialReference(object):
         Returns the EPSG SRID of this Spatial Reference, will be None if
         if undefined.
         """
-        return self.srs['AUTHORITY', 1]
+        try:
+            return int(self.attr_value('AUTHORITY', 1))
+        except ValueError:
+            return None
         
     #### Unit Properties ####
     def _cache_linear(self):
@@ -327,21 +330,21 @@ class SpatialReference(object):
         "Returns the WKT representation of this Spatial Reference."
         w = c_char_p()
         check_err(lgdal.OSRExportToWkt(self._srs, byref(w)))
-        return string_at(w)
+        if w: return string_at(w)
 
     @property
     def pretty_wkt(self, simplify=0):
         "Returns the 'pretty' representation of the WKT."
         w = c_char_p()
         check_err(lgdal.OSRExportToPrettyWkt(self._srs, byref(w), c_int(simplify)))
-        return string_at(w)
+        if w: return string_at(w)
 
     @property
     def proj(self):
         "Returns the PROJ.4 representation for this Spatial Reference."
         w = c_char_p()
         check_err(lgdal.OSRExportToProj4(self._srs, byref(w)))
-        return string_at(w)
+        if w: return string_at(w)
 
     @property
     def proj4(self):
diff --git a/django/contrib/gis/tests/test_gdal_geom.py b/django/contrib/gis/tests/test_gdal_geom.py
index 99631aa732..4b5c73b36d 100644
--- a/django/contrib/gis/tests/test_gdal_geom.py
+++ b/django/contrib/gis/tests/test_gdal_geom.py
@@ -148,6 +148,27 @@ class OGRGeomTest(unittest.TestCase):
                 for ring in poly:
                     self.assertEqual(sr.wkt, ring.srs.wkt)
 
+            mpoly = OGRGeometry(mp.wkt, 4326)
+            self.assertEqual(4326, mpoly.srid)
+            mpoly.srs = SpatialReference(4269)
+            self.assertEqual(4269, mpoly.srid)
+            self.assertEqual('NAD83', mpoly.srs.name)
+            for poly in mpoly:
+                self.assertEqual(mpoly.srs.wkt, poly.srs.wkt)
+                poly.srs = 32140
+                for ring in poly:
+                    self.assertEqual(32140, ring.srs.srid)
+                    self.assertEqual('NAD83 / Texas South Central', ring.srs.name)
+                    ring.srs = str(SpatialReference(4326)) # back to WGS84
+                    self.assertEqual(4326, ring.srs.srid)
+
+                    # Using the `srid` property.
+                    ring.srid = 4322
+                    self.assertEqual('WGS 72', ring.srs.name)
+                    self.assertEqual(4322, ring.srid)
+            
+
+
 def suite():
     s = unittest.TestSuite()
     s.addTest(unittest.makeSuite(OGRGeomTest))